Human immunodeficiency virus (HIV)-1 infection is a serious worldwide heath problem and one to which the forensic pathologist is frequently exposed. The lungs and the brain are frequently affected by HIV-1 infection, yet HIV-1 is rarely the cause of focal macroscopical lesions, requiring the histological examination of systematically sampled specimens. Opportunistic infections are usually the cause of focal lesions, cerebrovascular complications, and neoplasms while the changes attributed to HIV-1 include HIV-1 encephalitis, HIV-1 leukoencephalopathy, and HIV-1 myelitis. Meningeal lymphocytic infiltration and perivascular lymphocytic infiltration are generally seen in the early stages of HIV-1 infection. Other opportunistic infections often accompanying HIV-1 infection include a broad range of viral, parasitic, fungal, and bacterial infections as well as ischemic stroke, intracranial hemorrhage, lymphoma, and Kaposi sarcoma. One frequently noted autopsy finding in subjects with HIV-1 infection is brain involvement; HIV-1 generally enters the brain by being passively carried by T lymphocytes and monocytes. In children with HIV-1 infection, among the most common epidemiological findings are vascular mineralization, myelin pallor, and inflammatory infiltrates. However, in adults such opportunistic infections are relatively uncommon. While the cause of brain damage in HIV-1 infected individuals is not yet clearly understood, the development of brain lesions may be explained by the lack of effective immunological defense. Tables, figures, references